Intraoperative tumour detection using In-111-DTPA-D-Phe(1)-octreotide and a scintillation detector

Intraoperative tumour detection has been used in many applications. The exa mined tumour forms have varied and different detector systems and radiophar maceuticals have also been used. The aim of this study was to evaluate and compare the ability of an NaI(TI) scintillation detector to detect primary tumours and metastases in patients with different endocrine tumour types (e .g. carcinoid tumours, endocrine pancreatic tumours and thyroid tumours) an d in patients with breast carcinoma or benign thyroid lesions, on the basis of their somatostatin receptor expression after i.v. injection of In-111-D TPA-D-Phe(1)-octreotide. Thirty patients were injected with In-111-DTPA-D-P he(1)-octreotide intravenously. Scintigraphic images were taken 1 day after injection of the radio-pharmaceutical. and surgery was performed 1-7 days post injection. An NaI(T1) scintillation detector was used for intraoperati ve tumour detection. Tissue samples were collected during surgery for deter mination of In-111 activity concentration and histopathological examination . The scintigraphic images were positive in 29 out of 30 patients. Intraope rative tumour detection was successful in 43 of 66 collected biopsies: 10 o ut of 11 for carcinoid tumours. 7 out of 10 for medullary thyroid carcinoma (MTC) and 14 out of 22 for breast cancer. On the basis of our findings we conclude that intraoperative tumour detection with In-111-DTPA-D-Phe(1)-oct reotide using this NaI(TI) detector can be successful especially for carcin oid tumours and endocrine pancreatic tumours, due to the relatively high ac tivity concentrations in these tumour types, but is less successful in othe r forms of thyroid cancer, including MTC, and breast cancer. For successful intraoperative detection, the detector characteristics are also very impor tant, and further improvement of the detector systems is required to increa se the sensitivity and specificity.